The declared purpose of NEPA and the mission of the
NPS express very similar goals. Both contain language designed to result
in the conservation and protection of our nation's resources for the benefit
of future generations. NEPA was enacted for a simple reason: to make sure
that agencies fully consider the environmental costs and benefits of their
proposed actions before they make any decision to undertake those actions.

The
purpose of NEPA as stated in section 2 of the act that created it is to
encourage productive and enjoyable harmony between man and his environment;
to promote efforts which will prevent or eliminate damage to the environment
and biosphere and stimulate the health and welfare of man; and to enrich
the understanding of the ecological systems and natural resources important
to the Nation....

NEPA and the CEQ regulations have put two important
mechanisms in place to achieve this stated intent. One is the requirement
that all agencies make a careful, complete, and analytic study of the
impacts of any proposal that has the potential to affect the environment,
and alternatives to that proposal, well before any decisions are made.
The other is the mandate that agencies be diligent in involving any interested
or affected members of the public in the NEPA process.

Key features of the analysis are made available to
the public in one of three types of NEPA documents, depending on the degree
of impact to the environment and the process outlined in chapter
2.0 of this handbook. Generally, if the proposal clearly has no potential
for measurable environmental impact, it is categorically excluded (see
chapter 3.0) and a short 1- or 2- page notice is prepared. If it has the
potential for significant environmental impact, an environmental impact
statement, or EIS, is required (see chapter
4). If the proposed action would have a measurable impact on the environment,
or if it is unclear whether it has the potential for a significant impact,
an environmental assessment (EA) is the appropriate document to prepare
(see chapter 5). If the EA shows
the action may have a significant effect, an EIS is also required (unless
the provisions of section 5.2 (1)
apply). NEPA imposes many additional rules and requirements beyond this
simple strategy for determining which level of documentation is appropriate
for any given analysis. These rules are part of this handbook and should
be read carefully before you begin environmental impact work under NEPA.

The Organic Act creating NPS states that NPS will ...conserve the
scenery and the natural and historic objects and the wild life therein and...provide
for the enjoyment of the same in such manner and by such means as will leave
them unimpaired for the enjoyment of future generations (16 U.S. Code
1, the National Park Service Organic Act).

C. Early
planning

A
key feature of NEPA is that under the CEQ regulations (1502.5) all analysis,
public input, and documentation must be completed in time to be a useful
part of decision-making. Initiating or completing environmental analysis
after a decision has been made, whether formally or informally, is a violation
of both the spirit and the letter of the law. NEPA's intent is to encourage
planning for conservation and resource management and integration of scientific
and technical information into management decisions, rather than an after-the-fact
compliance effort. A well-done NEPA analysis provides useful
information on environmental pros and cons (i.e., impacts) of a variety
of reasonable choices (alternatives); this analysis is much like economic
cost-benefit or technical or logistical planning. It is an essential prelude
to the effective management of park resources.

D. A procedural act

NEPA's policies encourage agencies to incorporate environmental
information and public involvement in making decisions. The detailed and
scientifically valid study of impacts and alternatives, and appropriate
input from the public, must be available before a federal agency makes
any commitment of resources. It is up to the decision-maker how he or
she will use this information. If the only way to meet an essential agency
goal requires implementing an alternative with the potential for severe
adverse environmental impacts, this is ultimately allowed for under NEPA.
NEPA is therefore a procedural, or process-oriented, law,
rather than a substantive, or substance-oriented, one. Other
laws, including the Organic Act, are substantive and often prevent an
agency from taking action or pieces of an action that have too great
an impact on a particular resource. The process of environmental analysis
under NEPA provides the information that the NPS needs to make substantive
decisions for the long-term conservation of resources.

E. A substantive result

The information and analysis produced through the NEPA
process is used by the NPS in making management decisions about NPS administered
resources. In making these decisions the NPS is guided by the requirements
of the National Park Service Organic Act and related laws. The requirements
placed on the NPS by these laws, and especially by the Organic Act mandate
that resources are passed on to future generations unimpaired.
Impacts that are likely to or would result in impairment of resources
must be fully described and evaluated in environmental documents. In addition,
decision documents must confirm the nature and extent of impacts and whether
or not an impairment results from any of the alternatives analyzed or
selected for implementation.